ID PID SEQUENCE SERIES 1 0 01000000 2 1 01010000 5 2 01010100 6 2 01010200 3 1 01020000 4 3 01020100 7 4 01020101 ...My problem is when I assign ID 4 to have a PID of 1 and move it after ID 2, I would have to change the sequence of ID 4 to that of ID 3 or 01020000. Then recreate the sequence of ID 3 and its children. Now imagine this if you have thousands of PID=1 records. I will have to update every sequence after the insertion point recursively down to its children.